Carl Wilhelm Scheele James L. Marshall, Beta Eta '11, and Virginia R. Marshall, Beta Eta '03 Department of Chemistry, Universit¥ of North Texas, Denton TX 76203-5070, [email protected] he Genius of Scheele. Few chemists can boast as astonishing a career as that of Carl Wilhelm Scheele (1742-1786). (Figure 1). Living only for 44 years, this Swedish pharmacist discovered more elements (seven) than any other scientist (Note 1)-all before the era of modem chemistry of Lavoisier's Traite. 1 In the confines of a cramped home laboratory, Scheele also discovered a score of fundamental organic compounds and gases including tartaric acid, lactic acid, oxalic acid, citric acid, malic acid, uric acid, casein, glycerol, hydrogen sulfide, hydrogen fluoride, and hydrogen cyanide.'·' He developed a procedure for processing phosphorus from bones, replacing the previous inefficient procedure involving urea."' He discovered the action of light on silver salts, laying the foundation for black-and-white photography;' distinguished plumbago (graphite) and molyb denite (MoSi); and"above all"' discovered oy:ygen. With an amazing memory, he could read a book and thereafter use its contents without referring to it again.' His abilities and research so impressed the scientists of the Royal Academy of Sciences of Sweden that they elected him a member-although at that time (1775) he held merely the stahon of a pharmacist's apprentice. He declined an offer in 1777 to succeed Andreas Sigismund Margraff (1709-1782) as director of the Berlin Academy. Instead, shying from politics, he chose unpretentious surroundings so that he could work "without jealousy or malice" in his own pharmacy laboratory where his research could be done"without such hindrances."'

T Figure 2. Cities in which Scheele lived are underlined; they were all in Sweden, including Stralsund, which was then Swedish Pomerania.

Figure 3. "Scheele Haus,"the birthplace (1742) of Scheele, is the center building, located at Fiihrstrafie 23, Stra/sund, Gennany (N 54° 18.99; E 13° 05.56). This building is elegantly marked with a plaque and a small exhibit inside. The view is eastward, downhill toward the Baltic Sea only 200 meters away and from which cold winds often blow up the street. Occasional plaques in the city dating from the 1700s are engraved in Swedish, attesting to the fact that the region was part of Sweden at that time. 8

Scheele the Pharmacist and Chemist. During his career Scheele lived in six different cities (Figure 2). He was born in Stralsund, Germany (Figure 3), at that time Swedish Pomerania. His parentage was German, and throughout his life he used this language to write down his laboratory notes. He received an excellent education and experienced an enjoyable childhood painting and collecting insects and plants. At home he was particularly fascinated with the conver-

Figure 1. Statue of Scheele in Scheeleparken in Kiiping (N 59' 30.79; E 15° 59.47), which lies between Schee/e's grave and the Janner site of his phannacy. This statue was fashioned by Carl Milles, "the most famous Swedish sculptor" who has created many sculptures in promment sites in Sweden. Inset: Medal struck by the Swedish Academy 3 years after Schee/e's death. No authentic portrait of Scheele exists (Note 4). sations of the friends of his parents, who included doctors and pharmacists. At the age of 14 Scheele moved to Goteborg (Figure 4) to replace his brother Johann Martin, who had been· a pharmacist apprentice and who had died at the age of twenty. At this time, Goteborg was the center of economic prosperity, a showcase city embodying the wealth and power of Sweden. Here Scheele fell in love with the sumptuously provisioned stockroom of the pharmacy, and he is known to have experimented and studied 70 chemicalsevery one on the shelves except indigo. From borrowed textbooks of chemistry and pharma ~ cology he devoted himself to absorbing all possible knowledge on the subjects. He depended particularly on an old but famous textbook Laboratorium Chymicum (1716, posthumous) by Johann Kunckel (1630-1703), who, like Scheele, was a gifted and patient experimentalist.' THE HEXAGON

Figure S. 171is is the locatirm in Malmo (Gustaf AdolfTnrgct 1Offul/g11t1111 1I of the phamuicy (Fldkta Om: "Sprn1d Eagle") wl1crc Scheele worked during 1765-1768. Here he _first 0[15en1cd "sparks almvc snltpcfcr"which cvc11t11111/y led to his d1smucry of nxygrn. 111e original buildmg structures luwe bcc11 rep/need by late 11i11clcmlh cc11f11n1 lmildi11gs. The site of tl1c phannacy (at the comer of the buildmg) is now m1 elegant houtiquc (N 55' 36.13; £ 13' 00.02!

Figure 4. Giitrlmrg (Grtlw11b11~~) nm 11 prrsprrmis city wl1m Scl1ccli· was 11pl111n1111cy11ppm1tirr here 11757-1765!. The 11ppcr lwlf 15 a nwdrm u1cri 1, }l1ci11g wcshmrd. The rider l111ildi11gs rlatc _frrm tlir cnrly 1800s and lull'c replaced tl1c nng111al wnndm stmct11 res. Tl1c apntl1cc111:11 1i>l1cre Scheele worked !Enhiimingc11: "U11imm"; 11111rkcd with m111rmw! is 1ww 11 /JC1111t_11 s11lo11 ( ).) Sodra flm1111g11t1111 !"Smith Harhor Strrrf"; N :'il' 42.:lS; E 11 S7.84). The /owrr half is fiwn tlw li111c llf Sclwc/c, flmng cashoard. 71u' U11icom ph11n11acy is marked w1/h a1111rrom Across fi·ll111 !hr apotl1crnry was s1/11alcd !hr 1111clin11 a11d warchmiscs for the East l11d1a Cm11p@y, 110111 the lnmt1011 nf tire l11stnnrnl Stads11111scet. Jn both halves tl1c Christine K_ttrka (Christine Church! rn11 lw identified (upper: nght; lmocr: /cfi!. At 23 yeJrs of age, Scheele moved on to (Figure 5) where he had the advantages of a good laborntorv, and it was here he conducted his first serious experiments. He established a relationship with Anders Jahan Rctzius (1742-1821),' a demonstrator and later professor at the University of Lund (15 kilometers to the northeJst). Letters from Scheele to Rctzius exist' that allow us to gain a glimpse of his growing expencnce and C1mccpts oi chemistry at this time. In these letters Scheele gives a detailed description of his investigation of saltpeter and nitrous acid. Jn his classic treatisL' 011 Air and Fire: written a decade later in L:ppsala, Scheele describes his observation" how air-born bits of carbon were ignited from air generated from the boiling saltpeter." What he was observing was the spontaneous ignition of charcoal with generated oxygen, and he first observed this in Malmi1. We can be foirlv certain ~ialmo

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that this was the kcv observation that excited his im